content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.observable.internal.operators;
  
  import java.util.*;
  import java.util.concurrent.atomic.*;
  
  import io.reactivex.common.*;
  import io.reactivex.common.disposables.CompositeDisposable;
  import io.reactivex.common.exceptions.Exceptions;
  import io.reactivex.common.functions.Function;
  import io.reactivex.common.internal.disposables.DisposableHelper;
  import io.reactivex.common.internal.functions.ObjectHelper;
  import io.reactivex.observable.Observable;
  import io.reactivex.observable.ObservableSource;
  import io.reactivex.observable.Observer;
  import io.reactivex.observable.internal.observers.QueueDrainObserver;
  import io.reactivex.observable.internal.queues.MpscLinkedQueue;
  import io.reactivex.observable.internal.utils.NotificationLite;
  import io.reactivex.observable.observers.*;
  import io.reactivex.observable.subjects.UnicastSubject;
  
  public final class ObservableWindowBoundarySelector<T, B, V> extends AbstractObservableWithUpstream<T, Observable<T>> {
      final ObservableSource<B> open;
      final Function<? super B, ? extends ObservableSource<V>> close;
      final int bufferSize;
  
      public ObservableWindowBoundarySelector(
              ObservableSource<T> source,
              ObservableSource<B> open, Function<? super B, ? extends ObservableSource<V>> close,
              int bufferSize) {
          super(source);
          this.open = open;
          this.close = close;
          this.bufferSize = bufferSize;
      }
  
      @Override
      public void subscribeActual(Observer<? super Observable<T>> t) {
          source.subscribe(new WindowBoundaryMainObserver<T, B, V>(
                  new SerializedObserver<Observable<T>>(t),
                  open, close, bufferSize));
      }
  
      static final class WindowBoundaryMainObserver<T, B, V>
      extends QueueDrainObserver<T, Object, Observable<T>>
      implements Disposable {
          final ObservableSource<B> open;
          final Function<? super B, ? extends ObservableSource<V>> close;
          final int bufferSize;
          final CompositeDisposable resources;
  
          Disposable s;
  
          final AtomicReference<Disposable> boundary = new AtomicReference<Disposable>();
  
          final List<UnicastSubject<T>> ws;
  
          final AtomicLong windows = new AtomicLong();
  
          WindowBoundaryMainObserver(Observer<? super Observable<T>> actual,
                                              ObservableSource<B> open, Function<? super B, ? extends ObservableSource<V>> close, int bufferSize) {
              super(actual, new MpscLinkedQueue<Object>());
              this.open = open;
              this.close = close;
              this.bufferSize = bufferSize;
              this.resources = new CompositeDisposable();
              this.ws = new ArrayList<UnicastSubject<T>>();
              windows.lazySet(1);
          }
  
          @Override
          public void onSubscribe(Disposable s) {
              if (DisposableHelper.validate(this.s, s)) {
                  this.s = s;
  
                  actual.onSubscribe(this);
  
                  if (cancelled) {
                      return;
                  }
  
                  OperatorWindowBoundaryOpenObserver<T, B> os = new OperatorWindowBoundaryOpenObserver<T, B>(this);
  
                  if (boundary.compareAndSet(null, os)) {
                      windows.getAndIncrement();
                      open.subscribe(os);
                  }
              }
          }
  
          @Override
          public void onNext(T t) {
              if (fastEnter()) {
                  for (UnicastSubject<T> w : ws) {
                      w.onNext(t);
                  }
                  if (leave(-1) == 0) {
                      return;
                  }
              } else {
                  queue.offer(NotificationLite.next(t));
                  if (!enter()) {
                      return;
                  }
              }
              drainLoop();
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  RxJavaCommonPlugins.onError(t);
                  return;
              }
              error = t;
              done = true;
  
              if (enter()) {
                  drainLoop();
              }
  
              if (windows.decrementAndGet() == 0) {
                  resources.dispose();
              }
  
              actual.onError(t);
          }
  
          @Override
          public void onComplete() {
              if (done) {
                  return;
              }
              done = true;
  
              if (enter()) {
                  drainLoop();
              }
  
              if (windows.decrementAndGet() == 0) {
                  resources.dispose();
              }
  
              actual.onComplete();
          }
  
          void error(Throwable t) {
              s.dispose();
              resources.dispose();
              onError(t);
          }
  
          @Override
          public void dispose() {
              cancelled = true;
          }
  
          @Override
          public boolean isDisposed() {
              return cancelled;
          }
  
          void disposeBoundary() {
              resources.dispose();
              DisposableHelper.dispose(boundary);
          }
  
          void drainLoop() {
              final MpscLinkedQueue<Object> q = (MpscLinkedQueue<Object>)queue;
              final Observer<? super Observable<T>> a = actual;
              final List<UnicastSubject<T>> ws = this.ws;
              int missed = 1;
  
              for (;;) {
  
                  for (;;) {
                      boolean d = done;
  
                      Object o = q.poll();
  
                      boolean empty = o == null;
  
                      if (d && empty) {
                          disposeBoundary();
                          Throwable e = error;
                          if (e != null) {
                              for (UnicastSubject<T> w : ws) {
                                  w.onError(e);
                              }
                          } else {
                              for (UnicastSubject<T> w : ws) {
                                  w.onComplete();
                              }
                          }
                          ws.clear();
                          return;
                      }
  
                      if (empty) {
                          break;
                      }
  
                      if (o instanceof WindowOperation) {
                          @SuppressWarnings("unchecked")
                          WindowOperation<T, B> wo = (WindowOperation<T, B>) o;
  
                          UnicastSubject<T> w = wo.w;
                          if (w != null) {
                              if (ws.remove(wo.w)) {
                                  wo.w.onComplete();
  
                                  if (windows.decrementAndGet() == 0) {
                                      disposeBoundary();
                                      return;
                                  }
                              }
                              continue;
                          }
  
                          if (cancelled) {
                              continue;
                          }
  
  
                          w = UnicastSubject.create(bufferSize);
  
                          ws.add(w);
                          a.onNext(w);
  
                          ObservableSource<V> p;
  
                          try {
                              p = ObjectHelper.requireNonNull(close.apply(wo.open), "The ObservableSource supplied is null");
                          } catch (Throwable e) {
                              Exceptions.throwIfFatal(e);
                              cancelled = true;
                              a.onError(e);
                              continue;
                          }
  
                          OperatorWindowBoundaryCloseObserver<T, V> cl = new OperatorWindowBoundaryCloseObserver<T, V>(this, w);
  
                          if (resources.add(cl)) {
                              windows.getAndIncrement();
  
                              p.subscribe(cl);
                          }
  
                          continue;
                      }
  
                      for (UnicastSubject<T> w : ws) {
                          w.onNext(NotificationLite.<T>getValue(o));
                      }
                  }
  
                  missed = leave(-missed);
                  if (missed == 0) {
                      break;
                  }
              }
          }
  
          @Override
          public void accept(Observer<? super Observable<T>> a, Object v) {
          }
  
          void open(B b) {
              queue.offer(new WindowOperation<Object, B>(null, b));
              if (enter()) {
                  drainLoop();
              }
          }
  
          void close(OperatorWindowBoundaryCloseObserver<T, V> w) {
              resources.delete(w);
              queue.offer(new WindowOperation<T, Object>(w.w, null));
              if (enter()) {
                  drainLoop();
              }
          }
      }
  
      static final class WindowOperation<T, B> {
          final UnicastSubject<T> w;
          final B open;
          WindowOperation(UnicastSubject<T> w, B open) {
              this.w = w;
              this.open = open;
          }
      }
  
      static final class OperatorWindowBoundaryOpenObserver<T, B> extends DisposableObserver<B> {
          final WindowBoundaryMainObserver<T, B, ?> parent;
  
          OperatorWindowBoundaryOpenObserver(WindowBoundaryMainObserver<T, B, ?> parent) {
              this.parent = parent;
          }
  
          @Override
          public void onNext(B t) {
              parent.open(t);
          }
  
          @Override
          public void onError(Throwable t) {
              parent.error(t);
          }
  
          @Override
          public void onComplete() {
              parent.onComplete();
          }
      }
  
      static final class OperatorWindowBoundaryCloseObserver<T, V> extends DisposableObserver<V> {
          final WindowBoundaryMainObserver<T, ?, V> parent;
          final UnicastSubject<T> w;
  
          boolean done;
  
          OperatorWindowBoundaryCloseObserver(WindowBoundaryMainObserver<T, ?, V> parent, UnicastSubject<T> w) {
              this.parent = parent;
              this.w = w;
          }
  
          @Override
          public void onNext(V t) {
              if (done) {
                  return;
              }
              done = true;
              dispose();
              parent.close(this);
          }
  
          @Override
          public void onError(Throwable t) {
              if (done) {
                  RxJavaCommonPlugins.onError(t);
                  return;
              }
              done = true;
              parent.error(t);
          }
  
          @Override
          public void onComplete() {
              if (done) {
                  return;
              }
              done = true;
              parent.close(this);
          }
      }
  }
  